[LEAPSECS] Reliability

[Brian Garrett]

----- Original Message ----- 
From: "M. Warner Losh" <imp at bsdimp.com>
To: <leapsecs at leapsecond.com>; <seaman at noao.edu>
Sent: Monday, January 05, 2009 4:26 PM
Subject: Re: [LEAPSECS] Reliability



>

> All other users of time, it is widely agree, basically want everyone

> to agree on a time, have the sun basically overhead around noon, and

> do what they are told.  There's debate over what each of these loosey

> goosey terms means, and what the boundaries are for them.

>

>

> There is an important point to be made here.  The reason that DUT1

> matters to most people is for the sun overhead at noon feature.

> Sliding time zones solves that issue for many people, although there

> is much debate about the aesthetics of doing this.

>

>

Not being a member of the technical communities to whom this issue of leap 
seconds matters most, there's a limit on what I can contribute to this 
discussion.  However, I believe I can safely say that you time lords need 
not worry about what the general public thinks in regard to having clock 
time match the sun's position in the sky, or the "noon becomes midnight" 
scenario.  The unwarshed (sic) masses may have cared about that when society 
was still mostly agrarian (maybe farmers still do, but even they have to 
contend with DST imposed by us city folk :)), but very, very few of us get 
up with the chickens as a cultural necessity anymore.  Trust me, whatever 
becomes of leap seconds and DUT1, Joe the Plumber will be just fine.  For 
purposes of precise time and time interval, science and technology aren't 
merely the primary issue, they're the ONLY issue.



> Of course, I doubt there'd be more than a couple of these shifts

> before people realize that something else is needed.  There may never

> be a shift, but instead a change to a whole new time system as well

> that suits the needs of future generations better.  One that we cannot

> imagine from this vantage point in time.  Can you imagine being alive

> at the time of Christ and thinking you'd be able to measure the length

> of the day so accurately that you'd detect variations at the 1e-8

> level?  And even if you did, would you have the skills necessary to

> work out all the implications of that in advance?  Or that there'd be

> a standard written for it in a language that wasn't even around at the

> time?  This suggests, at least to some, that predicting what people

> will need and want over such long periods of time is difficult at

> best.  Both sides use this as part of their argument: the

> pro-leapsecond folks to say that it keeps things in sync, which gives

> future generations more options.  The anti-leapsecond folks to say

> that things will be so different, it just might not matter.

>

Well said.  The recurrent discussion of what imminent changes in timekeeping 
might mean for our posterity 500+ years from now is irrelevant because we 
have no way of knowing what their timekeeping needs or preferences might be.


Brian